Patent GB-810976-A (GB)
Title: Improvements in the bar stock feed of automatic lathes
IPC: B23B13/00
Filed: 1955-03-29
Abstract: 810,976. Automatic lathes. HAHN, O., and HAHN, E., [trading as INDEX WERKE KOMM. GES. HAHN & TESSKY]. March 29,1955 [May 13, 1954], No. 9208/55. Class 83 (3). A work-feeding device for an automatic lathe using bar-stock comprises a combined stock-feed and collet opening cam drum, driven by an auxiliary control shaft through a onerevolution clutch arrangement, through which a stock-feed-slide and feed tube are operated, the feed tube releasing the one-revolution clutch when the feed fingers slide off the end of a used bar by opening a first-engagement means, a hand-operated lever re-engaging the drive to the one-revolution clutch, and a second-engagement means for maintaining the clutch engagement until the feed slide is in its forward position with the collet opened, in which position the second-engagement means is released. The single hollow spindle of the machine, which is of known type, carries barstock 10, Fig. 2, fed by a feed tube 12 secured to a slide 15 and under control of a lever 26 and cam drum 19. The chuck is opened and closed by the movement of a sleeve 35 controlled by a lever 32 and cam 22. The latter is carried adjacent to and on the same auxiliary control shaft 18 as the cam 19. The shaft 18 is rotated by gearing 13, 38, Fig. 4, from a continuouslyrotated shaft 50 through a one-revolution clutch 42 for automatic rotation of the control shaft at the appropriate times during the workcycle of the machine, in accordance with known arrangements. Additionally, a hand-controlled clutch 51 is included in the drive to the onerevolution clutch, a lever 66 (broken lines, Fig. 3), pivoted in the machine frame at 64, operating this clutch as described below. Operation.-When the bar-stock is almost used up, the feed fingers in returning are no longer frictionally restrained, and a compression spring 83, Figs. 2 and 7, moves the lever 26 further in the anti-clockwise direction than when stock is present, by the amount of a depression in the cam groove 23 of the feed cam 19. A shaped pin 85 on the lower end of the cam lever 26 thus rides under, and moves to the right of, a corresponding pin 84 on a toggle device 79, 81, carrying a latch 76, Fig. 3. The lower member 81 of the toggle moves against a spring 86, Fig. 2, between the links, and is held at its lower free end by a stop 82 on the frame. On continued rotation of the cam 19 after this movement, the pin 85 in moving to the left again breaks the toggle and lifts the latch 76 (first-engagement means), Figs. 3 and 7. A lever 60, restrained by the latch, is thus released and turns anticlockwise, pulled by a spring 102, closing a switch 97 for a warning light, and operating through a rod 59 and lever 57, to disengage the clutch member 51. The drive to the control shaft and cams is thus stopped. with the chuck still closed. The operator, on the indication of the warning, moves the hand-lever 66 sufficiently to the left to engage a second latch arrangement 90, 91 (second-engagement means), Fig. 3, the lever 60 being moved by a member 67 on a lever 65 secured to the hand-lever spindle 64. The second latch engages before the previous latch arrangement 76, 77, so that the latter remains open in this case. The clutch 51 is re-engaged by the link 59 &c. and the cams start rotating again. In the meantime, the operator stops the spindle drive so that when a stop 16, attached to the collet slide, engages a lever 87 to trip the latches 90, 91 in a predetermined position with the chuck open, a new stock-bar can be fed into the machine, pushing out the waste-piece. The operator then restarts the spindle drive and moves the lever 60, this time to engage the first latch means 76, 77 and the drive clutch 51. The latches 90, 91 remain lifted by a stop 93, which rests on the top of the lever 60. The machine is then ready for a fresh set of operations on the new stock-bar.